Sexually transmitted diseases amplify the transmission of HIV, so detection and treatment of STDs represents a key part of HIV prevention. However, it remains unclear which STDs are of greatest importance in the HIV epidemic. In addition, the relative importance of STDs to HIV infectiousness and susceptibility have not been dissected. We have recently demonstrated that patients with acute HIV infection (HIV RNA positive, HIV antibody negative) can be detected through screening in STD clinics in North Carolina and Lilongwe, Malawi. Indeed, in Malawi 2.1% of men seeking care in our STD clinic had acute HIV infection. This Application is designed to better define acute HIV infection in STD patients in Malawi. In Aim 1 we will screen the clinic population for subjects with acute HIV infection, and enroll patients and control subjects and their sexual partners into a prospective study. In Aim 2 we will determine the correlation between different STDs and acute HIV infection. Using a new assay for early HSV infection (which detects antibodies with reduced avidity) we will examine the hypothesis that HSV and HIV have been co-transmitted. Comparing historical and lab data we will compare STDs and HIV in patients with acute HIV infection and their sexual partners. In Aim 3 we will compare genital secretions harvested from patients with acute and chronic HIV infection. We will examine the relationship between blood and genital secretions. We will determine the effects on STDs on genital tract viral burden, as defined (in men) by seminal plasma HIV concentration and the number of HIV infected seminal cells. The results of this study should help to define co-transmission of STDs and HIV, as well as the relative importance of HSV. The results should help to determine whether screening for acute HIV in STD clinics is feasible, and of benefit to individual or public health.